1. Field of the Invention
The present invention relates to a media conversion device for interconnecting communication terminal devices with media converted, and more particularly to a gateway device for interconnecting a plurality of communication terminal devices over a plurality of communications networks with media data handled by one of the communication terminal devices converted to media data that can be handled by another communication terminal device to thereby establish the communication between the communication terminal devices. The present invention also relates such a method therefor.
2. Description of the Background Art
Nowadays, telecommunications networks can handle a large variety of sorts of data by transmitting, for example, image data as on IP (Internet Protocol) or television telephony, or as in an instant message system that transmits text data on an end-to-end basis. For communication terminal devices connected to a telecommunications network, media conversion or, more precisely, multi-media format conversion, in conformity with a communication peer has been proposed for transmitting or receiving such media data.
In a communication terminal device, disclosed in Japanese patent laid-open publication No. 2006-210973, speech signals from a party on communication are converted into text displayed for viewing by a user of the communication terminal device, and the user enters a return message in the form of text on a keyboard, for instance, to be synthesized therefrom into a speech signal, which is in turn transmitted to a communication peer, to thereby enable talk with the communication peer on speech or television telephony, while the communication peer is talking with a further communication peer.
A media conversion device, disclosed in U.S. patent application publication No. US 2006/0026294 A1 to Virdi et al is provided in a server adapted to deliver contents, such as videos, by streaming over a telecommunications network, and determines communication media of a proper bit rate in dependence upon the bandwidth of the network over which client terminal devices are connected to a server to deliver contents with bit rates and communication media converted.
Between IP telephony or Internet connection business organizations, interconnections may sometimes be established. As is the case with communication media handled being of IP telephony involving multiple, different speech encoding or compression systems, there are cases in which, when interconnecting different networks, media converting gateway devices are placed on the boundaries between the networks to interconnect the terminal devices over the plural networks.
The communication terminal device taught by Japanese '973 publication and the media conversion device taught by Virdi et al are adapted to discriminate, when transmitting or receiving media data, the communication media between a conversion source and a conversion destination to perform the media conversion accordingly.
It was difficult for an intermediate device, such as a gateway device, arranged between terminal devices, to be unable to discriminate the communication media between the terminal devices of the source of transmission and the destination of transmission to perform the media conversion thereon.